System of wireless telegraphy.



PATENTED OCT.` 20

S. Gr. BROWN. SYSTEM 0F WIRELESS IELEGRAPHY.

APPLICATION FILED JAN. 23, 1900\ f 5l IIIIIIIIII tto. 741,6522.

atented October 20, 1905.

PATENT OFFICE.

SIDNEY GEORGE BROWN, OF BOURNEMOUTH, ENGLAND.

SYSTEM oF WIRELESS TELEGRAPHY.

SPECIFICATION forming part of Letters '.Patent No. 741,622, dated October 20, 1903.

Application iiled January 23,1900. Serial No. 2,483. (No model.) v

To a/ZZ whom it may concern/.-

Be it known that LSIDNEY GEORGE BROWN, electrician, a subject-of the Queen of Great Britain, residing at Van Buren, Poole Road, Bournemouth, in the county of Hants, England, have invented an Improved System of Wireless Telegraphy, of which the following is a specification.

This invention relates to an improved system of Wireless telegraphy, and has for its object to simplify and to increase the efficiency of the apparatus, to increase the speed of sig. naling, to enable messages to be transmitted to and received from one direction only, and to so adjust the apparatus that it is not at'- fected by and does not aect neighboring systems.

According to this invention the transmitting apparatus is provided with two radiating-wires coupled one to each terminal of the sparking device and the receiving apparatus is providedwith two receiving-Wires coupled one to each terminal of the coherer. These radiating and receiving wires are respectively placed at a distance apart which has a detinite relation to the length of the signalingwaves, that of half a Wave length or approximately half a wave length being the 'most convenient distance. This placing of the wires half a Wave length apart causes the sys'- tem to send its Waves to or receive them from mainly one direction, which direction would seem to be that of the plane of the wires. If the vertical wires Were not so carefully ad'- justed to the Wave length, they would transmit or receive the Hertzian Waves from any direction. By arranging a condenser across the high-potential terminals of the spark-coil and joining the terminals of this condenser to the spark-balls through highly-inductive coils I can increase the persistence of the Waves, the condenser acting as a storage of power and maintaining the potential at each side of the spark-gap. The highly-inductive coils prevent the charge in the condenser from itself oscillating across the spark-gap. By thus' increasing the persistence of the train of Hertzian waves due to each disruptive discharge the receiving-circuit can be caused tok be in tune or syntony with the transmittingcircuit, thus rendering the system more sensitive and less likely to be interfered with by neighboring systems differently disposed.

The Wave length that any system may generate is to a certain extent 'under command, and it is necessary iff'parabolic lreflectors are to be used to keepthe Waves short. E This can be done by suitably arranging the spark-gap, such as by employing suitablysized intermediate balls or'loy placing inductive coils in the arms of the radiating-wires. By thus keeping the length of the waves short the use of parabolic mirrors behind the radiating and receiving wires and within a much shorter' distance of said Wires than that of their length or half their length 'is rendered possible. These mirrors, which should be constructed of reticulated metal, such as fine wire-netting or its equivalent, have the eiect of reflecting the Waves to or receiving them from one definite direction, and thereby restricting the wave or telegraphic effect to' a given direction.

The coherer preferably employed is electrically or magnetically controlled in such manner that immediately after a signal has been received the electric or magnetic controlling force decoheres or renders the coherer non-conductive without the kintervention of a mechanical tapping device, thereby increasing the speed of signaling.

. In order that my invention may be clearlyl understood and readily carried into eect, I Will proceed to describe the same more fully in connection with the accompanying drawings, in which.

Figures l' and 2 ,are respectively diagrams of transmitting apparatus and receiving apparatus in Which the radiating and receiving Wires project Verticallyfinto the air. Fig. 3 Shows a parabolic mirror in position behind a radiating or a receiving Wire arranged according to this invention.

Referring to Figs. 1 and 2, a and a are the radiating-wires of the transmitting apparatus. a2 a3 are the receiving-Wires of the receiving apparatus and are preferably arranged in the same plane with the Wires a a'. b is the battery and t is the transmitting instrument in the primary circuit of the induction-coil c of the transmitting apparatus. K is a condenser, placed across the high-poten- IOO tial terminals of the secondary winding of the induction-coil c and in parallel with the wires a a. S S S are the spheres or balls of the sparking device. L Lr are inductive coils placed between the terminals of the condenser K and the terminals of the spark-balls S S, the ends of the radiating-wires ct a at one extremity -being also respectively connected to the terminals of the said sparkballs. o is a rotary vibrator, of well-known construction, placed in the primary circuit of the coil c. R is the receiving-relay or other receiving instrument. h is the battery in the circuit of the receiving-relay. d is the coherer in the receiving-relay circuit, to the terminals of which coherer the wires a2 a3 are connected. L2 L3 are inductive resistances placed, respectively, between the terminals of the coherer d and the receiver R and battery b; but in many cases the resistances L2 L3 are unnecessary, as the relay-winding R usually possesses suflicient inductance of its own. Upon depressing the key of the transmitter if the circuit of the battery Y) is closed and the primary winding of the coil c is energized through the vibratore in the well-known For fast-speed signaling this vibrator o, which makes and breaks the cu rrents for the primary Winding of coil c, should be kept constantly working whether the coil c is energized or not. When the coil c is thus energized,sparks pass between the balls S,and the Hertzian waves thereby generated are radiated by the wires a a. The condenser K acts as a storage of power, maintaining the potential at each side of the spark-gap, and thereby increasing the persistence of the Hertzian waves. The coils L L/ render slow the oscillation ofthe charge in the condenser, while permitting the currents from the secondary winding of the coil c to pass steadily to the spark-balls-that is to say, the inductances L L are of so high an impedance as to slow the oscillation of the charge in the condenser K, say, for example, to a period of one one-thonsandth of a second, while the period of the oscillation of the charge from the wires a a across the spark-gap would be of the order of one ten-millionth of asecond. The wires a d thus easily dissipate the electrical energy long before the charge in the condenser could itself produce even the fraction of one oscillation, and the condenser therefore acts as a steady supply of currentto the radiating system. When no signals are received, the coherer d is maintained in a decohered ornon' conductive condition in a manner hereinafter fully explained, and the circuit of the receiver R and battery b' is consequently open. lVhen the Hertzian waves cut the wires a2 a3 and induce therein voltages, the surgings thereby created pass through the coherer d, rendering it conductive and closing the circuit of the receiver R and battery b', the signals being vrecorded by the said receiver. The inductance in the relay-circuit, such as L2 L3,or the inductance possessed by the winding of the relay R itself prevents the surgings created by the I-Iertzian waves from lowing uselessly round the circuit. The radiating-wires d ct and also the receiving-wires a2 of* are respectively placed at a distance apart which has a definite relation to the length of the Hertzian waves. This distance may conveniently be approximately half that of a IIertzian wave length, such an' arrangement causing the positive radiating-wire to supply the positive crest of the wave at the same time as the negative radiating-wire su pplies the negative crest of the wave and the waves to be thus transmitted or received mainly in the direction of the plane of the radiating and receiving Wires.

By arranging the inductive coils L L and the condenser' K as above described the IIertzian Waves are kept persistent. The radiating and receiving wires being arranged and the persistence of the Waves being secured, as above described, permits tuning effects to be produced between the transmitter and receiver, so that they will be more sensitive to one another and will not be likely to be interfered with by differently-disposed neighboring systems. The shortness of the waves enables a parabolic mirror of wire-gauze or its equivalent, ase, Fig. 3, to be placed a short distance (not less than en efqurth of a waves length) behind the vertical wire or wiresfor the purpose of reliectingthe waves in a definite direction. Byconstructingthis reticulated reiiector mainly of a number of Vertical wires retained in position by as few horizontal crosswires as possible the Waves radiated are polarized, or the currents which produce them or which they themselves produce in neighboring or distant conductors are made to oscillate in the same plane as the radiatingwiresthat is, vertically. Any waves that may be radiated apart from those produced by the currents iowing in the vertical radiating-wires are either turned and radiated by the reflector in such manner as to set up currents in a distant vertical wire or pass through the refiector. The reflector is thus rendered more elicient than a solid screen would be.

l. In wireless-telegraph apparatus, means for generating etheric Waves in combination with a curved mirror comprising parallel wires adapted to rei-lect the waves in a definite direction.

2. In wirelesstelegraph apparatus, means for generating etheric waves in combination with a parabolic mirror comprising parallel Wires adapted to reflect the waves in a definite direction.

3. In wireless-telegraph apparatus, means for generating etheric Waves in combination with a curved mirror comprising parallel wires forming straight elements thereof and adapted to reflect the waves in a definite direction.

4E. In wireless-telegraph apparatus, means for generating etheric waves, in combination IIC with a parabolic mirror comprising parallel wires forming straight elements thereof and adapted to reliect the Waves in a definite direction. f

5 5. In wireless-telegraph apparatus, a metallic parabolic mirror composed in the main of vertically-arranged wires adapted to reflect the waves in a definite direction, substantially as lherein described. v

1o 6. In wireless-telegraph apparatus,the combination of a reticulated metallic parabolic mirror composed principally of vertical wires and a wave-radiating device substantially as herein described.

I5 7. In wireless-telegraph apparatus,the combination of a transmitter, a transmitting-battery and induction-coil, sparking spheres, a 'wave-radiating device, and a reticulated metallic parabolic mirror composed principally zo of vertical wires and placed behind said waveradiating device, substantially as described.

8. In wireless-telegraph apparatus, a receiving instrument, a coherer and a battery in the receiver-circuit, a wave-receiving de- 2 5 vice and av reticulated metallic parabolic mirror composed principally of vertical Wires and placed'behind the wave-receiving device,

substantially as described for the purpose specied.

9. In wireless-telegraph apparatus,the combination of a transmitter,a transmitting-battery and induction-coil, sparking spheres, a

-wave-radiating device, a reticulated metallic parabolic mirror composed principally of ver- 3 5 tical wires and placed behind the wave-'radiating device, a condenser placed across the highpotential terminals of the inductioncoil in order to maintain the potential at each side ceiving device and a reticulated metallic para- 45 bolic mirror composed principally of vertical Wires and placed behind the wave-receiving device, substantially as described Vfor the purpose specified.

10. In .wireless -telegraph apparatus, the combination of a transmitter, a transmittingbattery and induction-coil, sparking spheres, two parallel vertical radiating-wires attached one to each terminal of the sparking spheres and placed at a distance of half a wave length 5 5 apart, a reticulated metallic parabolic mirror placed behind the radiatingwires,a condenser placed across the high-potential terminals of the induction-coil, inductive coils placed'between the terminals of said condenser, and the )o terminals of Athe spark spheres, a receiving-relay, a coherer in the. receiving-relay circuit, two parallel vertical receiving-wires attached one to each terminal of the coherer and placed at a distance of half awave length apart, and 65 a reticulated metallic parabolic mirror placed behind the receiving-Wires, substantially as described, for the purpose specified. Y

In testimony whereof I have hereunto set my hand, in presence of two subscribing wit- 7o nesses, this 9th day of January, 1900.

SIDNEY GEORGE BROWN.

Witnesses:

J. COLLINS, WALTER J. SKERTEN. 

